Have you checked your feeders in the very early morning-5:30 to 6:00 AM & late in the evening at dusk? Those times, during the 3 to 5 weeks thru May and into the first weeks of June are usually the only times I see them. They are apparently, too busy conducting their personal business to grace us with more frequent appearances. By July and August their humming threat attack charges (when I stand too close to a feeder), scrapping, tag playing, arguing and territorial displays become everyday occurrences making garden reveries difficult!